I would not use the phrase "go out." That sounds like a date. I would find some other means to signal that this is professional. As others are saying, inviting

I would not use the phrase "go out." That sounds like a date. I would find some other means to signal that this is professional. As others are saying, inviting someone to grab a coffee in the break room is much less likely to sound like romantic interest than saying something like "go out for coffee." Try phrases like this: Meet for coffee. Grab a coffee together. Let's discuss (professional thing) over coffee.